"New Approach Oregon" has spent 2.3 million dollars in TV advertising.
The new ads that will hit airwaves within days, feature drug treatment expert Richard Harris.
"I'm the former Director of Addiction and Mental Health Division. Drug treatment is woefully underfunded right now and Measure 91 would better fund drug treatment and prevention programs. Marijuana isn't going anywhere. We're not stopping it with the war on drugs."
Much of the money for these ads come from out of state.
It is expected to be the most expensive pro-marijuana campaign in the state's history.
Oregonians voted down a similar measure two years ago, but polls show a majority of people in the state support this measure.